BACKGROUND The gut microbiota participates in the metabolism of substances and energy, promotes the development and maturation of the immune system, forms the mucosal barrier, and protects the host from pathogen attacks. Although the pathogenesis of cholesterol gallstones is still not clear, studies have suggested that gut microbiota dysbiosis plays an important role in their formation. METHODS Microbial DNA from faeces of normal control patients and those of patients with calculi was subjected to 16S rRNA gene sequencing to detect gene expression changes in intestinal microbes. ELISA kits were used to measure free bile acids, secondary bile acids and coprostanol according to the manufacturer's instructions. The relationship between flora and their metabolites was then analysed. RESULTS In the gallstone group, the diversity of intestinal bacteria and the abundances of certain phylogroups were significantly decreased (p < 0.05), especially Firmicutes (p < 0.05), the largest phylum represented by the gut microbiota. This study found an increase in free bile acids (p < 0.001) and secondary bile acids (p < 0.01) in the enterohepatic circulation. Bile salt hydrolase activity was not related to the abundances of BSH-active bacteria. 7a-dehydroxylating gut bacteria were significantly increased (p < 0.01), whereas cholesterol-lowering bacteria were significantly reduced (p < 0.05). The Ruminococcus gnavus group could be used as a biomarker to distinguish the gallstone group from the control group. CONCLUSION We conclude that intestinal flora imbalance affects bile acid and cholesterol metabolism and is associated with gallstone formation.

中文翻译：

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肠道菌群失衡会影响胆汁酸代谢，并与胆结石形成有关。

背景技术肠道菌群参与物质和能量的代谢，促进免疫系统的发育和成熟，形成粘膜屏障，并保护宿主免受病原体的侵袭。尽管胆固醇胆结石的发病机理尚不清楚，但研究表明肠道菌群失调在其形成中起着重要作用。方法对正常对照组和结石患者粪便中的微生物DNA进行16S rRNA基因测序，以检测肠道微生物中基因表达的变化。根据制造商的说明，使用ELISA试剂盒测量游离胆汁酸，仲胆汁酸和coprostanol。然后分析了菌群与其代谢产物之间的关系。结果在胆结石组，肠道细菌的多样性和某些系统群的丰度显着降低（p <0.05），尤其是以肠道菌群为代表的最大系统菌种Firmicutes（p <0.05）。这项研究发现肠肝循环中游离胆汁酸（p <0.001）和仲胆汁酸（p <0.01）增加。胆汁盐水解酶活性与BSH活性细菌的丰度无关。7a-去羟基化肠道细菌显着增加（p <0.01），而降低胆固醇的细菌显着减少（p <0.05）。念珠菌组可以用作区分胆结石组和对照组的生物标志物。结论我们得出结论，肠道菌群失衡会影响胆汁酸和胆固醇代谢，并与胆结石形成有关。